Why do TV and VCR tuners require a matched Varactor diodes? On the previous slide we have illustrated the principle of TV/VCR tuner architecture. In order to have an optimum alignment, a minimum spread between the Varactor diodes is required. Capacitance variations across a wafer are unique for each wafer. And the major task is to keep closely matched Varactor diodes together. This process has become known as the Direct Matching Assembly process, or DMA process.